package gl.java.network.transport.kcp.example.rtt;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;

/**
 * Measures RTT(Round-trip time) for TCP.
 * <p>
 * Receives a message from client and sends a response.
 */
public class TcpRttServer {

    static final int PORT = Integer.parseInt(System.getProperty("port", "8009"));

    public static void main(String[] args) throws Exception {
        // Configure the server.
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(group)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        public void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline p = ch.pipeline();
                            p.addLast(new TcpRttServerHandler());
                        }
                    }).childOption(ChannelOption.TCP_NODELAY, true);

            // Start the server.
            ChannelFuture f = b.bind(PORT).sync();

            // Wait until the server socket is closed.
            f.channel().closeFuture().sync();
        } finally {
            // Shut down all event loops to terminate all threads.
            group.shutdownGracefully();
        }
    }

}
